In the femoral replacement surgery, a surgeon uses a measurement gauge to measure a size of a patient's femur so as to select an implant with suitable size and an implanting position according to the size obtained by the measurement gauge. Thereafter, a resection block corresponding to the size of implant is used to guide a cutting tool for the femoral resection.
The surgeon selects, according to the condition of patient's femur, one of the measurement gauge from different measurement gauges, each measurement gauge having different reference datum. One of the measurement gauge uses an anterior cortex as the reference datum to fix a front resection position of the femur, and thereafter a rear resection position of the femur is adjusted according to the size of the implant. Another one of the measurement gauge uses a posterior condyle as the reference datum to fix a rear resection position of the femur, and thereafter a front resection position of the femur is adjusted according to the size of the implant. However, when the patient's femur happens to be with size just between two implanting implants, the selection of either one of the measurement gauges will cause a problem that there will always be with over or insufficient resection of the anterior portion or the posterior portion to thus adversely affect the mobility of the patient's knee after the surgery.
In order to enhance the accuracy of the femoral resection, which can therefore achieve a perfect match between the implant and the patient's femur, the surgeon have to prepare different measurement gauges, each with different reference datum, and plural cutting blocks, each corresponding to every different size of implant. Therefore, the quantity of the femoral resection instruments becomes increased to cause a higher purchase cost and a larger storage space of the femoral resection instruments.